In the railway field, it is known to apply various apparatuses to identify wagons belonging to a convoy moved by a motor unit, some of which provide a connection by a cabled network between the wagons, while others provide to transmit an identification of the wagons.
For example, U.S. Pat. No. 6,114,974, EP-A-1.0314.88 and U.S. Pat. No. 5,651,517 use a reading of a gradient of a physical quantity along the train to identify the composition thereof, and require a cabled connection.
Another apparatus is known, based on GPS localization, in which the localization information of a wagon are sent on a cell network to the central unit for comparison between the localization information and the railway network.
Again in this field, document WO-A-01/49546 is known, which teaches an apparatus and a method based on the processing of the GPS signal to determine the order and orientation of locomotives moved together in railway stations or yards.
These systems are effective if the vehicles to be traced remain stationary for a long time, or in any case when the response times required of the identification and/or serialization system are in the order of at least some minutes.
Otherwise, these systems cannot be used in practice to identify entities moved together, mainly because of the limitations of use imposed by the reception of a GPS signal:
localization error in some cases comparable with the size of the vehicle analyzed;
possible unavailability of the GPS information when required;
latency times of the localization information typically varying from a few seconds to a few minutes, depending on the last fix, the state of the satellites and other, hence comparable with the overall expected identification times;
cost and additional complexity of the solution for each vehicle to be identified, also with regard to installation and maintenance.
In order to try and overcome some of the limitations described above, document DE-A-102007040165 uses a temporal reference supplied by the GPS receiver installed on every vehicle together with a local timer to memorize the timetables or timestamps in which the vehicle is subjected to an acceleration event, and to make deductions on the composition of the convoy by comparing the sequence of temporal events recorded by the motor unit with the one received by each vehicle in the vicinity that can be reached by the radio transceiver installed on the motor unit. This comparison allows to identify the starting states of the individual vehicle. The method described in DE-A-102007040165 remains subject to the intrinsic limitations of GPS technology, in particular the unavailability of an adequately precise temporal reference in correspondence with the acceleration event to be memorized, in all conditions of accelerated motion, not only at start-off. Furthermore, the method is not suitable when the entities moved together are constrained differently to the tractor vehicle, for example a wagon and a transported baggage, since the stress detected from the two entities may have a considerably different trend and entity, and may not be correctly detected by the same sensor. Moreover the method is weak in particular but not improbable conditions such as the simultaneous departure of two or more adjacent trains in a railway yard. In order to compensate this intrinsic weakness of the identification method it is provided to use other kinematic quantities, such as speed, distance traveled, direction of motion or geo-localization of the vehicle which typically, however, are deduced from the GPS signal when available. Finally the method proposed in DE-A-102007040165 does not allow to make deductions on the nature of the entities moved together.
To identify carriages during or after the convoy has been made up, current systems use electronic devices that dialog with a supervisor device using cable connections installed in the carriages and along the whole convoy, or by means of wireless networks. However, to prevent a device from dialoging erroneously with the supervisor of another train that is under radio cover, wireless networks generally need specific configurations with every movement of a carriage, which is very disadvantageous and burdensome for the management of the convoy.
In particular, document US-A-2008269957 is known, which provides a system to determine the order of the wagons once it is known which wagons belong to the train, also called serialization procedure. The system is based on the detection of environmental quantities to which the mean in motion is subjected, with the corresponding sending of an announcement message on the communication network. In this known solution, each carriage must be identified in advance with a univocal carriage identification. Furthermore, this known system requires a personalized wireless communication method between the various devices of the carriages, in which there is a communication on a first frequency, known in advance in the station, and a communication on a second frequency known in advance, different from the first frequency, when in motion.
Further apparatuses are known, costly and complex to maintain, which comprise “radar columns” positioned near the station, to discriminate the localization of one wagon with respect to an adjacent one.
Apparatuses are also known that provide passages where an RFID tag is read, at exit from the station, which record the RFID codes of the carriages of a train in transit. This known solution also requires a costly infrastructure which impacts with the structure of current stations.
A solution is also known that is based on viewing systems, in which a TV camera at exit from the station acquires the images of the sides of all the carriages in transit and in particular interprets a graphical ID applied. In this case too, it is an infrastructure that is complex to manage and maintain.
Another solution is also known, based on wireless TAGs, but these are not robust in the case of trains near to stations or adjacent in motion at almost constant speed, and require manual configurations.
It is also known that it is necessary to enable several devices for communication and access to information services so that they can communicate with each other and/or with a supervisor device in wireless mode. Access to such wireless networks is regulated by security keys consisting of sequences of bits, and the devices can dialog with each other or with a possible supervisor if they possess said keys. At present no limit to association and access to a determinate network is given to the devices as a consequence of being transported or not being transported by the same vehicle, or moved together. Therefore, devices which, as a pre-requisite, are in radio visibility, which use the same protocols and which possess the appropriate security keys can dialog with the same supervisor or among themselves even if they are transported by different vehicles from that of the supervisor. This is the case, for example, of devices that are on different trains, but at distances such as to be all under the same radio cover.
However, there are situations in which the knowledge of the access key for a particular radio network by a device is made difficult or impossible by the movement of the device, its location on the mean that implies a bad or difficult radio cover, or a logistic of use, which can require connection to a radio network for example of a train on which the device is transported, without there being any possibility of informing the device about which the access key to said network of that particular train is. Furthermore, a device may request to be connected to another device of the same train without either of the two knowing in advance the access key to the data radio network.
One purpose of the present invention is to obtain an apparatus and a corresponding method that overcome the limits of the state of the art, allowing to identify correctly and effectively entities moving together, that is, to identify that said entities belong to a determinate convoy in movement.
Another purpose is to identify said entities in movement together during or after the convoy has been put together by means of wireless network and without needing specific configurations.
Another purpose is the automatic identification of only those entities moving in an integrated motion, without using cabled networks or when there is even a temporary lack of reception of the GPS geo-localization signal or other form of connectivity with a remote central control unit.
Another purpose is to automatically enable access of the entities to communication and information services of a convoy of only the radio network of the transport vehicle.
Finally, another purpose is to discriminate the nature of the entities moved together, for example in the case of railways, between carriages and baggage transported or mobile electronic devices carried by passengers.
The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.